Integrated Nanostructured Systems

Live-animal whole body optical image of mouse following injection of antibody-conjugated quantum rods (green color).

Polymers; photonics; biophotonics; nanomedicine; optics.

Professor Prasad is one of the early pioneers and most widely recognized by the international community for his seminal contributions to the field of nonlinear optical effects in molecules and polymers. Through more than a decade of numerous ground breaking theoretical and experimental works, Professor Prasad has made a major contribution to the fundamental understanding of the interplay of structure and energy state dynamics to produce a specific nonlinear optical response.

More recently, his contributions have been in the new field of "Nanophotonics." His efforts have focused on creating a fundamental understanding of nonlinear optical processes at the nanometer size scale, developing novel concepts for the design of nanostructured optical materials, and probing interactions and dynamics of nonlinear processes.

He has also contributed to developing another new field, "Biophotonics," which utilizes light-matter interaction to probe biological structure and functions at the cellular, tissue and organism levels, leading to novel methods of optical diagnostics and light-activated therapy. Professor Prasad has again focused on applications of nonlinear optical techniques for Biophotonics.

"Shape Control of CdS Nanocrystals in One Pot Synthesis," K.-T. Yong, Y. Sahoo, M. T. Swihart, P. N. Prasad, J. Phys. Chem. C 111(6) 2447-2458, 2007.

"Organically Modified Silica Nanoparticles Co-Encapsulating Photosensitizing Drug and Aggregation-Enhanced Two-Photon Absorbing Fluorescent Dye Aggregates for Two-Photon Photodynamic Therapy," S. Kim, T. Y. Ohulchanskyy, H. E. Pudavar, R. K. Pandey, and P. N. Prasad, J. Am. Chem. Soc. 129(9) 2669-2675 (2007).

"A Quantum Chemical Approach to the Design of Chiral Negative Index Materials" A. Baev, M. Samoc, P.N. Prasad, M. Krykunov, and J. Autschbach, Optics Express 15(9) 5730-5741 (2007).

"Water Dispersible Polymeric Structure Co-encapsulating a Novel Hexa-Peri-Hexabenzocoronene Core Containing Chromophore with Enhanced Two-Photon Absorption and Magnetic Nanoparticles for Magnetically Guided Two-Photon Cellular Imaging," Q. Zheng, T. Y. Ohulchanskyy, Y. Sahoo, and P. N. Prasad, J. Phys.Chem.C (In press)

"Quantum Rod Bioconjugates as Targeted Probes for Confocal and Two-Photon Fluorescence Imaging of Cancer Cells," K.-T. Yong, J. Qian, I. Roy, H. H. Lee, E. J. Bergey, K. M. Tramposch, S. He, M. T. Swihart, A. Maitra, P. N. Prasad, Nano Letters (3) 761-765 (2007).

"Aggregation-Enhanced Fluorescence in Organically Modified Silica Nanoparticles: A Novel Approach toward High-Signal-Output Nanoprobes for Two-Photon Fluorescence Bioimaging," S. Kim, H. E. Pudavar, A. Bonoiu, and P. N. Prasad, Adv. Mater, 19, 3791, (2007)

"Formation of ZnTe Nanowires by Oriented Attachement:," K.-T. Yong, Y. Sahoo, Z. Hao, M. T. Swihart, J. R. Minter, , P. N. Prasad, Chem. of Mater (Commun) 91, 4108-4110 (2007)

"Three Color Reflector Fabricated with Holographic Photopolymers," V. K. S. Hsiao, A. N. Cartwright, P. N. Prasad, K. R. Maskaly, and E. L. Thomas, manuscript under preparation.

"Controllable One-Dimensional Photonic Bandgap (PBG) Structure Based on Photopolymer Systems," V. K. S. Hsiao, A. N. Cartwright, P. N. Prasad, P. F. Lloyd, and T. J. Bunning, manuscript under preparation.

"Optical trapping of director structures and defects in liquid crystals using laser tweezers," I. I. Smalyukh, D. Kaputa, A. V. Kachynski, A. N. Kuzmin, and P. N. Prasad, Opt. Express. 15, 4359-4371 (2007)

"Phase-sensitive Time-modulated Surface Plasmon Resonance Polarimetry for Wide Dynamic Range Biosensing," P. P. Markowicz, W.C. Law, A. Baev, P.N. Prasad, S.Patskovsky, A.V. Kabashin, Opt. Express 15(4) 1745-1754 (2007).

"CARS microscopy of three-dimensional director structures in thermotropic liquid crystals," A.V. Kachynski, A.N. Kuzmin, P.N. Prasad, and I.I. Smalyukh, Appl. Phys. Lett (Accepted)

"Stimulated Rayleigh-Bragg Scattering in a Three-Photon Absorbing Medium and Its Phase-Conjugation Property," G. S. He, Q. Zheng, P. N. Prasad, J. Opt. Soc. Amer. 24, 1166-1177 (2007).

"Saturation of Multiphoton Absorption Upon Strong and Ultrafast Infrared Laser Excitation," G. S. He, Q. Zheng, A. Baev, P. N. Prasad, J. Appl. Phys. 101, 083108 (2007).

"Two-Photon Absorption Based Optical Limiting and Stablization by Using a CdTe Quantum Dot Solution Excited at Optical Communication Wavelength of 1300 nm," G. S. He, Q. Zheng, K.-T. Yong, A. I. Ryasnyanskiy, P. N. Prasad, Appl. Phys. Lett. 90, 181108 (2007).

"New Method for Delivering a Hydrophobic Drug for Photoddynamic Therapy Using Pure Nanocrystal
Form of the Drug," K. Baba, H. E. Pudavar, I. Roy, T. Y. Ohulchanskyy, Y. Chen, R. K. Pandey, P. N. Prasad, Molecular Pharmaceutics 4(2), 289-297 (2007).

"Flexible Thiopyrylium and Selenopyrilium Photosensitizers for Purging Blood-borne Pathogens and Producing Photoinitiated DNA Cleavage," T. Y. Ohulchanskyy, M. K. Gannon, M. Ye, A. Skripchenko, S. J. Wagner, P. N. Prasad, M. R. Detty, J. Phys. Chem. B. 111(32), 9686-9692 (2007)

"Imaging Pancreatic Cancer Using Surface-functionalized Quantum Dots," J. Qian, K.-T. Yong, I. Roy, T. Y. Ohulchanskyy, E. J. Bergey, H. H. Lee, K. M. Tramposch, S. He, A. Maitra, P. N. Prasad, J. Phys. Chem. B. 111(25) 6969-6972 (2007)

"Structure-Activity Relationship Among Purpurinimides and Bacteriopurpurinimides: Trifluoromethyl Substituent Enhanced the Photosensitizing Efficacy." A. Gryshuk, Y.Chen, L. Goswami, S. Pandey, J. R Missert, T. Ohulchanskyy, W. Potter; P.N. Prasad, A. Oseroff, R.K. Pandey, Journ. of Med. Chem. 50 (8), 1754-1767 (2007).

"Efficient photodetection at IR wavelengths by incorporation of PbSe-carbon-nanotube conjugates in a polymeric nanocomposite." N. Cho, K.R. Choudhury, R. B. Thapa, Y. Sahoo, T. Ohulchanskyy, A. Cartwright, K.-S. Lee, P.N. Prasad. Advanced Materials 19 (2), 232-236 (2007).

"Shape control of CdS nanocrystals in one-pot synthesis" Ken-Tye Yong, Yudhisthira Sahoo, Mark T. Swihart, and Paras N. Prasad J. Phys. Chem C, 111(6) (2007) 2447-2458.

"Gold Nanorods Coated with Multilayer Polyelectrolyte as Contrast Agents for Multimodal Imaging," H. Ding, K.-T. Yong, I. Roy, H. E. Pudavar, W. C. Law, E. J. Bergey, P. N. Prasad, J. Phys. Chem C. 111, 12552-12557 (2007)

"Negative Refractivity Assisted Optical Power Limiting," A. Baev, E. P. Furlani, M. Samoc, P. N. Prasad, J. Applied Phys. 102, 043101 (2007)

"Multi-Photon Excitation Properties of CdSe Quantum Dots Solutions and Optical Limiting Behavior in Infrared Range," G. S. He, K.-T. Yong, Q. Zheng, Y. Sahoo, A. I. Ryasnyanskiy, A. Baev, P. N. Prasad. Optics Letters Express 15, 12818-12833 (2007)

"Polymeric Nanocomposite Infrared Photovoltaics Enhanced by Pentacene," P. R. Thapa, K. R. Choudhury, W. J. Kim, Y. Sahoo, A. N. Cartwright, P. N. Prasad, Appl. Phys. Lett. (in press).

"Wide Dynamic Range Phase-sensitive Surface Plasmon Resonance Biosensor Based on Measuring the Modulation Harmonics" W.C. Law, P. Markowicz, K.T. Yong, I. Roy, A. Baev, S. Patskovsky, A.V. Kabashin, H.P. Ho and P.N. Prasad, Biosensors and Bioelectronics J.Biosensors and Bioelectronics, Vol.23, Iss 5/15, Pgs 627-632,(2007)

"Templated Synthesis of Gold Nanorods (NRs): The Effects of Cosurfactants and Electrolytes on the Shape and Optical Properties," Ken-Tye Yong, Yudhisthira Sahoo, Mark T. Swihart, Paul M. Schneeberger, Paras N. Prasad "Topics in Catalysis (special issue)" (in press).

"Organically modified silica nanoparticles with covalently incorporated photosensitizer for photodynamic therapy of cancer," T. Y. Ohulchanskyy, I. Roy, L. N. Goswami, Y. Chen, E. J. Bergey, R. K. Pandey, A.R. Oseroff, P. N. Prasad1, Nano Letters (in press)

"Intraparticle Energy Transfer and Fluorescence Photoconversion in Nanoparticles: An Optical Highlighter Nanoprobe for Two-Photon Bioimaging," S. Kim, H. Huang, H. E. Pudavar, Y. Cui, P. N. Prasad, Chem. Mater. Vol.19, pp 5650. 2007,

"Multi-Photon Absorbing Materials: Molecular Designs, Syntheses, Characterizations, and Applications," G. S. He, L.-S. Tan, Q. Zheng, P. N. Prasad, Chemical Reviews (2007) (accepted).

"Size Dependent Raman and Infrared Studies of PbSe Nanoparticles," F. S. Manciu, Y. Sahoo, F. Carreto, P. N Prasad, J. Raman Spectroscopy (Submitted).

"Optical trapping of director structures and defects in liquid crystals using laser tweezers" I. I. Smalyukh, *, D.S. Kaputa, A.V. Kachynski1, A. N. Kuzmin,and P N. Prasad, 2 April 2007 / Vol. 15, No. 7 / OPTICS EXPRESS 4359, 2007

"Coherent anti-Stokes Raman scattering polarized microscopy of three-dimensional director structures in liquid Crystals" A. V. Kachynski, A. N. Kuzmin, and P. N. Prasad, Appl. Phys. Lett. 91, 15,1905/2007